What is “Environmentally Relevant”? A Framework to Advance Research on the Environmental Fate and Effects of Engineered Nanomaterials

2021 ◽  
Author(s):  
Mark C Surette ◽  
Jeffrey Alan Nason ◽  
Stacey Harper ◽  
Denise M Mitrano
Keyword(s):  
Environmental Fate ◽  
Engineered Nanomaterials ◽  
Significant Progress ◽  
Knowledge Gaps ◽  
Advance Research

Environmental nanoscientists and nanotoxicologists have made significant progress towards understanding the various factors and processes that impact the environmental fate and effects of engineered nanomaterials (ENMs); nevertheless, many knowledge gaps...

Aquatic Mesocosm Strategies for the Environmental Fate and Risk Assessment of Engineered Nanomaterials

2021 ◽  
Author(s):  
Andrea Carboni ◽  
Danielle L. Slomberg ◽  
Mohammad Nassar ◽  
Catherine Santaella ◽  
Armand Masion ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Environmental Fate ◽  
Engineered Nanomaterials

scholarly journals Improving the prediction of environmental fate of engineered nanomaterials by fractal modelling

2017 ◽  
Vol 99 ◽  
pp. 78-86 ◽  
Author(s):  
S. Avilov ◽  
L. Lamon ◽  
D. Hristozov ◽  
A. Marcomini
Keyword(s):  
Environmental Fate ◽  
Engineered Nanomaterials

scholarly journals A Review on the Environmental Fate Models for Predicting the Distribution of Engineered Nanomaterials in Surface Waters

2020 ◽  
Vol 21 (12) ◽  
pp. 4554
Author(s):  
Edward Suhendra ◽  
Chih-Hua Chang ◽  
Wen-Che Hou ◽  
Yi-Chin Hsieh
Keyword(s):  
Surface Waters ◽  
Environmental Fate ◽  
Flow Analysis ◽  
Material Flow Analysis ◽  
Engineered Nanomaterials ◽  
Environmental Matrices ◽  
Quantitative Measurements ◽  
Predicted Environmental Concentrations ◽  
Averaged Models ◽  
Analysis Models

Exposure assessment is a key component in the risk assessment of engineered nanomaterials (ENMs). While direct and quantitative measurements of ENMs in complex environmental matrices remain challenging, environmental fate models (EFMs) can be used alternatively for estimating ENMs’ distributions in the environment. This review describes and assesses the development and capability of EFMs, focusing on surface waters. Our review finds that current engineered nanomaterial (ENM) exposure models can be largely classified into three types: material flow analysis models (MFAMs), multimedia compartmental models (MCMs), and spatial river/watershed models (SRWMs). MFAMs, which is already used to derive predicted environmental concentrations (PECs), can be used to estimate the releases of ENMs as inputs to EFMs. Both MCMs and SRWMs belong to EFMs. MCMs are spatially and/or temporally averaged models, which describe ENM fate processes as intermedia transfer of well-mixed environmental compartments. SRWMs are spatiotemporally resolved models, which consider the variability in watershed and/or stream hydrology, morphology, and sediment transport of river networks. As the foundation of EFMs, we also review the existing and emerging ENM fate processes and their inclusion in recent EFMs. We find that while ENM fate processes, such as heteroaggregation and dissolution, are commonly included in current EFMs, few models consider photoreaction and sulfidation, evaluation of the relative importance of fate processes, and the fate of weathered/transformed ENMs. We conclude the review by identifying the opportunities and challenges in using EFMs for ENMs.

scholarly journals Investigating the OECD database of per- and polyfluoroalkyl substances – chemical variation and applicability of current fate models

2020 ◽  
Vol 17 (7) ◽  
pp. 498 ◽  
Author(s):  
Ioana C. Chelcea ◽  
Lutz Ahrens ◽  
Stefan Örn ◽  
Daniel Mucs ◽  
Patrik L. Andersson
Keyword(s):  
Environmental Fate ◽  
Chemical Diversity ◽  
Acid Dissociation ◽  
Substantial Part ◽  
Chemical Variation ◽  
Training Set ◽  
Knowledge Gaps ◽  
Diverse Range ◽  
Wide Range ◽  
Polyfluoroalkyl Substances

Environmental contextA diverse range of materials contain organofluorine chemicals, some of which are hazardous and widely distributed in the environment. We investigated an inventory of over 4700 organofluorine compounds, characterised their chemical diversity and selected representatives for future testing to fill knowledge gaps about their environmental fate and effects. Fate and property models were examined and concluded to be valid for only a fraction of studied organofluorines. AbstractMany per- and polyfluoroalkyl substances (PFASs) have been identified in the environment, and some have been shown to be extremely persistent and even toxic, thus raising concerns about their effects on human health and the environment. Despite this, little is known about most PFASs. In this study, the comprehensive database of over 4700 PFAS entries recently compiled by the OECD was curated and the chemical variation was analysed in detail. The analysis revealed 3363 individual PFASs with a huge variation in chemical functionalities and a wide range of mixtures and polymers. A hierarchical clustering methodology was employed on the curated database, which resulted in 12 groups, where only half were populated by well-studied compounds thus indicating the large knowledge gaps. We selected both a theoretical and a procurable training set that covered a substantial part of the chemical domain based on these clusters. Several computational models to predict physicochemical and environmental fate related properties were assessed, which indicated their lack of applicability for PFASs and the urgent need for experimental data for training and validating these models. Our findings indicate reasonable predictions of the octanol-water partition coefficient for a small chemical domain of PFASs but large data gaps and uncertainties for water solubility, bioconcentration factor, and acid dissociation factor predictions. Improved computational tools are necessary for assessing risks of PFASs and for including suggested training set compounds in future testing of both physicochemical and effect-related data. This should provide a solid basis for better chemical understanding and future model development purposes.

scholarly journals Engineered Nanomaterials: Knowledge Gaps in Fate, Exposure, Toxicity, and Future Directions

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Arun Kumar ◽  
Prashant Kumar ◽  
Ananthitha Anandan ◽  
Teresa F. Fernandes ◽  
Godwin A. Ayoko ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Engineered Nanomaterials ◽  
Future Research ◽  
Accurate Estimation ◽  
Knowledge Gaps ◽  
Environmental Media ◽  
Toxicity Studies ◽  
Open Questions ◽  
Living Organisms ◽  
Exposure Conditions

The aim of this study is to identify current knowledge gaps in fate, exposure, and toxicity of engineered nanomaterials (ENMs), highlight research gaps, and suggest future research directions. Humans and other living organisms are exposed to ENMs during production or use of products containing them. To assess the hazards of ENMs, it is important to assess their physiochemical properties and try to relate them to any observed hazard. However, the full determination of these relationships is currently limited by the lack of empirical data. Moreover, most toxicity studies do not use realistic environmental exposure conditions for determining dose-response parameters, affecting the accurate estimation of health risks associated with the exposure to ENMs. Regulatory aspects of nanotechnology are still developing and are currently the subject of much debate. Synthesis of available studies suggests a number of open questions. These include (i) developing a combination of different analytical methods for determining ENM concentration, size, shape, surface properties, and morphology in different environmental media, (ii) conducting toxicity studies using environmentally relevant exposure conditions and obtaining data relevant to developing quantitative nanostructure-toxicity relationships (QNTR), and (iii) developing guidelines for regulating exposure of ENMs in the environment.

scholarly journals Perfluoroalkyl and polyfluoroalkyl substances: current and future perspectives

2011 ◽  
Vol 8 (4) ◽  
pp. 333 ◽  
Author(s):  
Kurunthachalam Kannan
Keyword(s):  
Environmental Fate ◽  
Environmental Chemistry ◽  
Environmental Pollutants ◽  
The United States ◽  
Perfluoroalkyl Substances ◽  
Future Research ◽  
Knowledge Gaps ◽  
Environmental Distribution ◽  
Global Environmental ◽  
Made In

Environmental contextPerfluoroalkyl substances were recognised as global environmental pollutants 10 years ago. Although considerable advancements have been made in our understanding of the environmental distribution, fate and toxicity of perfluoroalkyl substances, several important issues remain to be resolved. This article identifies existing knowledge gaps that deserve further investigations to enable meaningful regulatory decisions. AbstractIt has been over a decade since perfluoroalkyl substances (PFASs) were discovered as global environmental contaminants. Considerable progress has been made in our understanding of the environmental fate and toxic effects of PFASs since then. Government regulations and voluntary emission reduction initiatives by industry have been effective in reducing environmental and human exposure to a major PFAS, perfluorooctane sulfonate (PFOS), in the United States and several other western countries. Although significant advances have been made in our understanding of the environmental chemistry of PFASs, considerable knowledge gaps still exist in several areas of environmental fate and risk assessments. Owing to their complex chemistry, involving existence of multiple precursors with significant numbers of structural isomers and mixtures of homologues, multiple degradation pathways and unique physicochemical properties, challenges remain in elucidating sources and environmental fate. In this overview, some of the knowledge gaps in PFASs’ research have been identified and suggestions for future research have been made.

Toward quantitative defect analysis using HREM

1994 ◽  
Vol 52 ◽  
pp. 714-715
Author(s):  
David J. Smith
Keyword(s):  
Electron Microscope ◽  
Unit Cell ◽  
Defect Analysis ◽  
Significant Progress ◽  
Detailed Characterization ◽  
Small Unit ◽  
Resolution Electron ◽  
High Resolution Electron Microscope ◽  
Large Unit Cell ◽  
Made In

The electron microscope has evolved to the level where it is now straightforward to record highresolution images from thin samples (t∼10 to 20nm) that are directly interpretable in terms of atomic arrangements. Whilst recorded images necessarily represent two-dimensional projections of the structure, many defects such as dislocations and interfaces may be linear or planar in nature and thus might be expected to be amenable to detailed characterization. In this review, we briefly consider the recent significant progress that has been made in quantitative defect analysis using the high-resolution electron microscope and then discuss some drawbacks to the technique as well as potential scope for further improvements. Surveys of defect modelling for some small-unit-cell materials and interfaces have recently been published, and reference should be made to other papers in this symposium for further examples.The technique of structure imaging originated in the early '70s with observations of large-unit-cell block oxides.

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